1. Field of the Invention
The field of the invention relates to gas operated firearms where gases flow from the firearm barrel into an operating piston which actuates an automatic mechanism for extraction, ejection, feeding, and the chambering of ammunition. The particular improvement of the invention is a metering device inserted into a cylinder, thereby controlling the flow of gases into the operating piston.
2. Description of the Prior Art
Attempts have been made in the prior art to control the volume of the gases that flow into operating pistons which actuate automatic mechanisms, for extracting, ejecting, feeding, and chambering ammunition in firearms such as shotguns. These attempts involve the venting of surplus gases to the atmosphere and have met with success when firing shotgun shells having relatively low pressure; however, when heavier loads, such as a magnum shot shell is utilized, severe hardship on firearm mechanisms occurs, and to alleviate this situation, special model firearms are manufactured for the heavy magnum loads or special barrels are used which restrict the flow of gases by means of a smaller gas orifice in the barrel. If the size and area of the orifices in the barrel could be adjusted smaller or larger, the gases entering the actuating piston could be controlled. This method, however, is impractical in the normal course of manufacturing and the herein invention provides a solution to the problem as described in detail hereinafter.